If burning 1 kg of lignite coal releases 18 MJ of energy, how much energy will be released when 250 g of lignite is burnt?

Step-by-step solution

1. Convert 250 g to kilograms: $250\text{ g}=0.25\text{ kg}$.
2. Multiply the energy per kg: $0.25\text{ kg}\times 18\text{ MJ/kg}=4.5\text{ MJ}$.
3. State the result.

Concept tested: Energy content of coal

Published 16 October 2026 · How this solution was prepared and checked